Process for securing jackets on electrode insulators



Jan. 6, W. S. THOMAS PROCESS FOR SECURING JACKETS ON ELECTRODE INSULATORS {119d 1920 2 Sheets-Shoat 1 Y My; 5 u Z ,1 Z M wh ,f\ 4 [a M //V V I W1 4 2 W M 9 gm z F N .Y 4. %//A .3 Z; g u

. "mternal Patented Jen -'6, v

UNITED STATES.

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Application flied lebruary lg, 1820. Serial No. 857,728.

To all whom a may comm:

Lock Haven, in the county of Clinton and State of Pennsylvania, have invented certain new and useful Improvements in Procfor Securing Jackets on Electrode Insulators, of which the following is a specification.

Readily removable electrode insulators for spark pluis, such for example as used in com ustion engines, are usually provided with metallic jackets for the purpose of taking the thrust of the clamping land nut when the. latter is used to secure e electrode insulator to the body portion 0f= 'the'{spark plug. It is quite obvious that the above mentioned metallic jackets fare n for the purpose specified for the reason t at insulators are usually made of porcelain or other non-metallic material which is cracked and that it would not ..be practical to jam nuts or other binding the metallic 'ackets to operative or cause-the same to ,..portions'fdirectly against the porcelain inf'sulator. However, it has long been a source of trouble and a diflicult problem to apply t 'e orcelain 1n.- sulators fort e reason that if the jacket is clamped with sufiicient pressure against {the porcelain insulator so as to prevent leakage of the products of combustion and also ftrgingversecurrent leakage there is a posthat in securing the jacket to the porce ain insulator the insulator will be .cracked' and thereby destroy the value of the insulator and render it either totally inermit current leakage through the cracks portion of the insulator. Another of the past 'difliculties in jacketing porcelain insulators made prior to my invention is that unless there is possible chance for expansion of the ina su ator which necessarily occurs due to the extremely high temperature to which the insulator is subjected, the insulator is liable to Y crack for the'reason that it will jam against portions of the jacket which are unyieldable.

One object of my invention is to provide an improved process'whereby jackets of the above described type can be placed upon porcelain or other insulators in such manner that they will not cause the cracking of the insulator either during the application of the jacket to the insulator or' during the Another object is to so carry out my improved process that when the jacket is a plied to an insulator an efiicient seal will e provided between the insulator and the jacket to prevent passage of oils or products of combustion therebetween and at the same time the insulator will be free to expand and contract within the'jacket without causing cracking of the insulator orany detrimental eflect to the insulator.

The insulators of the above type usually have an enlarged portion between their ends; said enlarged portion bein in the form of an annularly extending ange.

Another object of my lIlVBlltlOll' is to so place a jacket upon an insulator of the above type that the jacket will be confined entirely to said flange and so that no portion of the jacket will engage the insulator above or below said flange. Thus an insulator hav- .PATENT' OFFICE.

of the insulator as a part of a spark Be it known that I, WILLIAM S; Tnoms, l a citizen of the United States, residingat ing a jacket pllaced thereon by my improved ave said jacket secured to its Figures 1 to 8 inclusive are elevational views, partly in section showing various steps followed in carrying; out my improved process of applying a jacket to an electrode insulator.- Figure 9 is an elevation view of an insulator having a jacket secured thereon by my improved process, and

Figure 10 is an enlarged fragmentary view, partly in section, showing a jacket havin been placed upon an electrode insu lator y my mproved process.

Referring to the drawings, 11 represents a central sectional elevation of a base or primary die which at its top has a recess 12; the bottom of the recess forming a shoulder 13. A hole 14 extends through the body of the die 11 from the recess downwardly and a flange 15 surrounds the recess. The top 16 below the flange 15 forms a ledge for a urpose hereinafter described. A metallic acket 17 which is shown in central section in Figure 1, has a cylindrical portion 18 of IOU tar as the u the same diameter as that of the recess 12 and is ada ted to fit within the recess and rest upon file shoulder 13 as clearly shown in Figure 2. The jacket 17 is hollow 1n the form of a collar and the flange 19 (projects upwardly from the )ortion 18; sai flange having its inner sur ace of the same diameer part of the inner surface of the cylin rical portion 18. However, the flange 19 is of less external diameter than the external diameter of the cylindrical or tion 18 so that a. ledge 20 is rovided. he extreme top portion ofthe ange 19 is beveled or chamfered inwardly as shown at 21. The lower part of the inner surface of the cylindrical portion 18 is curved inwardl to a smaller diameter as shown at 22 and a ole 23 extends through the cylindrical portion 18; said hole being of less diameter than the internal diameters of the cylindrical ortion 18 and flan e 19. Thus an inwardy projecting annu ar flange 24 is provided.

After placing the jacket 17 within the recess 12 as above described a ring washer 25 is inserted within the jacket as shown in Figure 3. This ring washer is of less external diameter than the internal diameters of the flange 19 and upper partof the cylindrical portion 18 but is of greater external diameter than the diameter of the hole 23. Thus the ring washerrests upon the curved surface 22 of the inwardly projecting annular flan e 24.

An e ectrode insulator 26, which may be made of orcelain, has an enlar ed annular flange 27 etween its ends 28 an 29. After the rin washer 25 has been inserted within the jac et as shown at Figure 3, the insulatoris placed within the acket so that the lower surface of the flange 27 rests on the upwardly curved surface 30 of the ring washer 25 and the lower end 29 of the insulator extends through the ring washer 25, hole 23 of the jacket 17 and into the hole 14 of the base die 11. The flange 27 of the insulator is of less external diameter than the internal diameters 'of the upper part of the cylindrical portion 18 and flange 19 of the jacket 17. Thus there is a space 31 provided between the flange 27 and the jacket 17.. After the insulator has thus been inserted as shown in Figure 4, a to die 32 is placed upon the base die 11; said top die having a cavity 33 into which the flange 15 of the base d1e 11 fits. An inwardly extending flange 34 of the top die 32 above the cavity 33 snu ly' fits around the flange 19 of the 'acket 1 below its top and rests upon the ledge 20 of the jacket 17, as clearly shown in Figure 5. Thus a hole 35 is produced by the flange 34 through which the flange 19 of the acket 17 rojects, and a recess 36 extends upwardly rom the flange 34 to the upper surface of the top die 32. With this construction it will be noted that the portion of the flan e 19 of the 'acket 17 above the flange 34 of t e top die 3 extends into the recess 36 of the top die. After the top die has thus been placed, a second ring washer 37 is drop ed over the end 28 of the insulator 26 and t is washer 37 has a downwardly curved surface 38 which fits against the top rounded ed e 39 of the flange 27 of the insulator 26. The ring washer 37 is of less external diameter than the internal diameter of the flan e 19 of the jacket 17 and the flange 27 of t e insulator 26 is of such height or width that when thus positioned the ring washer 37 will be at a level below the to of the flan e 19; The rin washers 25 an 37 are preferably made 0 a softer metal than that from which the jacket 17 is made, for example the jacket 17 may be made of steel and the ring washers 25 and 37 may be made of copper.

After the ring washer 37 has thus been placed, a primary plunger die 40 which has a sleeve portion 41 for encircling the upper end of the electrode insulator 26 is inserted within the recess 36. This plunger die 40.

has an inwardly curved surface 42 which is of such diameter and curvaturethat when moved downwardly u on the chamfered upper edge 21 of the ange 19 as shown in lgure 6, the upper edge portion of the flange 19 will be turned over the top of the ring washer 37. However it is important here to note that the extreme edge ortion 21 is not bent inwardly a suflicient istance to touch the insulator 26. In other words, as clearly shown in Figure 6, a space 43 exists between the edge 21 and the insulator 26.

After the upper edge portion of the jacket flange 17 has thus been turned, the primary plunger die 40 is removed from the recess 36 and a collar 44 is inserted within the recess 36 as clearly shown in Figure 7. This collar is of an internal diameter equal to the external diameter of the jacket flange 19 which has not been turned inwardly and the lower end of the collar 44 rests on the top of the flange 34. This collar 44 provides another recess 45 into which the lower sleeve end 46 of a secondary plunger die 47 is inserted. The lower end 48 of the secondary plunger die 47 is curved from a diameter less than the diameter of the hole formed by the turned-in edge 21 to a diameter greater than that of the hole formed by the turned-in edge 21 so that when the die 47 moves inwardly the inner part 49 of the die will pass within the hole formed by said turned-in edge 21 of the jacket flange 19 and the remaining part of the curved surface 48 will bend the edge portion 21 of the jacket downwardly to provide a hooked flange and at the same time will compress the ring washers 25 and 37 against the top and bottom rounded edges of the insulator flange 27 and the inner surface of the jacket.

It will be noted however that the part 49 of the secondary plunger die 47 will prevent any portion of the jacket flange 19 from between said surface 22 and the lower rounded edge of the insulator flange 27. Thus the space 31 above described will be preserved between the ring Washers 25 and 37 and the ad'acent surfaces of the flange 27 and jacket 1 This space will permit ex- -pansion and also serve as an insulating s ace and by an inspection of Figure 10 it wil be noted that any strain which is placed upon the insulator will occur directly against the enlarged and strong flange 27. Furthermore in view of the above described steps of my improved process, the pressure exerted by the ring washers 25 and 37 will be diagonally across the flange 27 and in this manner the weaker portions of the insulator will be free of any strains due to pressure'exerted between the jacket, the ring washers and the insulator.

Having thus described my invention,

what T claim as new and desire to secure by Letters Patentis 1. The process herein described which consists in providing an electrode insulator with an enlarged flange; placing the flange within a jacket; positioning a die to sur round the jacket and engage with an edge portion thereof, and compressing the edge portion of the jacket inward and downward to form a hook-shaped flange adapted to lock the jacket to the insulator flange but free from engagement with the body of the insulator. I I

2. The process herein described which consists in providing an electrode insulator with an enlarged flange; placing the flange within a jacket having an inwardly extending and an axially extending flange; positioning a die over and partly within the axially extending flange, and compressing said flange inward and downward in the form of an inner rolled edge adapted to lock the jacket to the insulator flange but free from contact with the body of the insulator. 3. The process herein described which consists of providing an electrode insulator with an enlarged flange between its ends; then providing a jacket having an inwardly extending flan'ge and an axially extending flange; then inserting said insulator flange within the jacket; then compressing the ed e of said axial flange simultaneously throng out its circumference in the direction of its length and toward the axis thereof to provide an inturned edge extending toward but spaced from the portionof the insulator at the outer side of said enlarged flange; and finally compressing said turned edge of the jacket inwardly over said enlarged flange of the insulator in the form of an inturned hooked flange and at the same time including means between the turned edge and said ortion of the insulator whereby the hooked ange is kept from touching said portion of the nsulator.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

WILLIAM S. THOMAS.

Witnesses ANNA BENTON, Gms. E. Po'rrs. 

